The invention relates to a device for controlling a beam of electro-magnetic radiation comprising two composed elements and an electro-optic medium between these elements, each of the elements successively comprising a substrate layer, an electrode layer and an orientation layer, each of the orientation layers facing the electro-optic medium and the electro-optic medium being switchable between at least two states. The invention also relates to an image display panel. Such panel may be used in a direct view display apparatus or in an image projection apparatus, for example for video applications, or as a monitor. The device of the invention may also be used in a wavelength selector or in a beam direction controller.
A device as mentioned in the opening paragraph is described in U.S. Pat. No. 5,262,882. In this patent, a liquid crystal cell is shown with orientation layers of an oriented polymer comprising liquid crystal material. Due to the strong interaction between the orientation layer and the switchable liquid crystalline material, the latter is oriented in the direction of orientation of the oriented polymer.
If such a cell is used in a display or shutter application, it is usually placed between two mutually crossed polarizers. The first polarizer transmits one of the polarization components of the incident visible radiation and absorbs the other polarization component. Dependent on the voltage across the cell the polarization direction of the transmitted component is more or less rotated and partly or entirely transmitted by the second polarizer. The radiation which is not transmitted by the second polarizer is absorbed by this polarizer. Moreover, radiation losses due to reflections at the polarizers surfaces may occur so that considerably more than 50% of the radiation incident on the first polarizer is lost.